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How does an app like TextNow provide free calls and texts without a carrier?
Can I port my existing phone number into the app?
How does the app stay secure while handling personal communication?
This article provides a technical guide to building a full-featured app like TextNow. It covers key components such as VOIP integration, phone number provisioning, and ad-based monetization. You'll also learn to deliver free calling, texting, and data without relying on traditional carriers.
Can an app be built that offers free calls, texts, and data without using traditional mobile carriers?
As more people look for low-cost ways to stay connected, interest in services like TextNow is growing fast. These users want freedom from contracts, bills, and extra fees. But making an app like this takes more than a good idea. You’ll need real-time voice systems, virtual phone numbers, and strong security.
This blog shows how to build an app like TextNow from the ground up. From VOIP to monetization, each part is covered in simple terms.
Ready to create something users will rely on? Let’s start.
Understand how to create an app like TextNow from backend to frontend.
Learn about VOIP, free calling, and real-time messaging services.
Explore architecture diagrams, feature sets, and security best practices.
Compare options for Google Voice, free phone numbers, and ads for monetization.
Get a technical breakdown of handling calls, texting, and data synchronization.
Before writing a single line of code, understand what makes an app like TextNow successful.
| Feature | Description |
|---|---|
| Free Phone Number | Assign users a phone number to send and receive texts and calls. |
| Free Calls & Texting | Let users make free calls and send text free messages using Wi-Fi or mobile data. |
| Unlimited Talk & Calling | Offer unlimited calling either within the US or with nationwide talk plans. |
| Google Voice Integration | Optional porting or linking to google voice for easier user migration. |
| Multiple Devices | Allow login and conversation sync across phones, tablets, and computers. |
| Receive Verification Codes | Support platforms that require verification codes, even when not using a carrier. |
| Ad-Supported Free Plans | Monetize with ads in the free version while offering paid no-ad tiers. |
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Choosing the right technology ensures you can scale, support unlimited data plans, and meet high security standards.
| Component | Tech Stack |
|---|---|
| Real-Time Communication (RTC) | WebRTC, Twilio Programmable Voice, Agora |
| Messaging API | Firebase, Socket.IO, PubNub |
| Database | PostgreSQL, Redis (for caching), MongoDB (for logs) |
| Authentication | OAuth 2.0, Firebase Auth |
| Verification Codes | Twilio Verify, Nexmo |
| Media Storage | AWS S3 (for photos, voicemails, maps) |
| Phone Number Management | Twilio, Bandwidth, Plivo |
Mobile App: Flutter, React Native, Swift (iOS), Kotlin (Android)
Web App / Desktop: React.js + Electron for computer support
A major part of building an app like TextNow is phone number assignment and call routing.
Session Initiation Protocol (SIP) for managing calls
RTP for real-time voice transmission
Handling dropped calls and retry logic
Security: TLS encryption for call data and SRTP for voice
To support text-free communication and send texts, integrate:
Firebase Realtime Database or PubNub for real-time sync
Message queuing via RabbitMQ for delivery attempts and retries
Security for personal and group messaging
Make sure users can:
Send/receive messages
Attach photos
Sync across devices
Access message history from a computer or phone
Connection is critical. You need to optimize for:
Wi-Fi first, then mobile data
Support SIM-free devices for a truly free phone experience
Optional upgrades for unlimited data plans
| Type | Benefit |
|---|---|
| Wi-Fi | Preferred for free calls and texting |
| Mobile Data | Supports free phone service on-the-go |
| SIM (Optional) | Only for fallback voice/SMS, not needed for google voice or app-only solutions |
Focus on the following key features in your MVP:
Signup/Login with email or your existing phone number
Get a free phone number assigned
Text free and make free calls via Wi-Fi
View history and send texts
Handle verification codes
Offer unlimited talk (ad-supported or paid)
To keep the free phone experience:
Use ads from AdMob, Facebook Audience Network
Rewarded video ads for bonus data or more features
In-app purchases to remove ads or unlock unlimited data plans
Be transparent: avoid hidden fees and confusing bills. Let users easily compare plans.
Allow users to:
Sync accounts across multiple devices
Use the app on a computer and a phone
Maintain the account with their existing phone number
Support friends, family, and conversation continuity
Security is non-negotiable.
Protect:
Call and text content (end-to-end encryption)
User identities and phone numbers
Sessions and access tokens
Stored photos, maps, and message metadata
Use:
End-to-end encryption (E2EE) for messaging
Secure WebSockets
Encrypted media with expiring URLs
Regular review and penetration testing
Plan for:
Continuous review and update cycles
User support for bugs, calls, or connection issues
Horizontal scaling with Kubernetes or serverless functions
CDN usage to reduce interrupt latency
| Component | Estimated Time | Estimated Cost |
|---|---|---|
| MVP Development | 3-5 months | $20,000 – $50,000 |
| Infrastructure | Monthly $300–$2000 | Variable |
| VOIP Services | Per minute/msg | Based on usage |
| Ongoing Support | Continuous | Based on team |
Costs vary based on:
Developer rates
Service usage
Use of paid data, SIM, and premium features
An app like TextNow meets today’s need for free calls, texts, and numbers without contracts or high monthly bills. With VOIP, cloud support, and ad-backed revenue, you can offer a smart, low-cost service that works well and scales fast.
As users move away from traditional carriers, now is a great time to create a better way for them to stay connected, on their terms.
